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New product: A-Star 32U4 Robot Controller with Raspberry Pi Bridge
I am excited to announce our new A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge, a general-purpose robot controller based on Atmel’s ATmega32U4 microcontroller.
This new robot controller is the latest model in our A-Star line of Arduino-compatible USB microcontroller boards. We started with the A-Star 32U4 Micro and have been gradually expanding the line, adding peripherals and various form-factor and voltage options, with the goal of eventually replacing our older Orangutan robot controllers. The Zumo 32U4 was a major step in that direction, since its controller board is essentially an A-Star 32U4 plus extra peripherals for motor control and sensing. But while the Zumo 32U4 is a complete robot kit, this board is for people who want to design their own robot.
The A-Star 32U4 Robot Controller LV includes most of the features of the A-Star 32U4 Prime LV, including an Arduino-compatible USB bootloader, an efficient step-up/step-down regulator, and handy peripherals like the buzzer and buttons, and it expands on the A-Star line by adding a pair of Texas Instruments DRV8838 1.8 A motor drivers, the same motor drivers as on the Zumo. All of the AVR’s GPIO lines are broken out, and we have included handy power and ground rails so you can easily connect lots of things like servos and sensors:
This board is well-suited for small robots that would have otherwise used an Orangutan controller like the SV-328 or SVP-1284. While we did not include an LCD like on the Orangutans, you can get far better display, monitoring, or data logging by making use of the Raspberry Pi connection, which I will talk about next.
Using the robot controller with a Raspberry Pi
The Raspberry Pi is a great board for an embedded project that needs serious computational power or connectivity. We have released a couple of Raspberry Pi motor driver boards over the past year, which give you a way to get started exploring robotics with your Raspberry Pi. But robotics projects tend to use a lot of analog sensors, timing-sensitive devices like servos, and other peripherals that are not compatible with the limited I/O capabilities of the Raspberry Pi. These types of things are what microcontrollers are designed for, so you can do a lot more if you pair your Raspberry Pi with a complete microcontroller board.
That’s why instead of using the standard Arduino form factor like the Prime, we built the A-Star 32U4 Robot Controller LV to double as a Raspberry Pi HAT:
A-Star 32U4 Robot Controller LV with Raspberry Pi Bridge on a Raspberry Pi Model B+. |
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The Robot Controller fits on top of a Raspberry Pi A+/B+/2, powers the Pi, and connects to it as an I²C slave device, giving you a bidirectional channel of communication between the two processors. We have broken out all of the GPIO of the Raspberry Pi, and there are a few general-purpose level-shifters included on the board to help you experiment with other communications protocols or interface other hardware to your system. We even include the EEPROM required by the HAT specification, though we have not found it to be particularly useful – we ship it blank and unlocked for you to experiment with.
For more information about the A-Star 32U4 Robot Controller LV, or to order, see the product page. You can also check out our open-source A-Star 32U4 Arduino library, which provides easy access to the main features of the Robot Controller, including its motor drivers; we will be adding examples showing I²C communication with the Raspberry Pi soon.
New distributors in Asia
To wrap up this round of distributor introductions, I would like to welcome the following new Pololu distributors in Asia:
See the full list of over 200 distributors to find one in your area.
New distributors in South America
Continuing with our belated new distributor introductions, we are happy to welcome these six new Pololu distributors in South America:
See the full list of over 200 distributors to find one in your area.
New distributors in Europe
Continuing to catch up on our new distributor introductions, we are excited to welcome these new European distributors:
Now, here is that cool video of TME’s warehouse:
See the full list of over 200 distributors to find one in your area.
Memorial Day weekend sale
We are having a big Memorial Day sale now through Monday, with discounts on over 600 products when you use the coupon code MEMORIALDAY15. Stock up on robot parts now so you can build cool things all summer long! Note that we will be closed on Monday, so orders will not ship until Tuesday, May 26.
For more information, including all of the sale items, see the sale page.
New high-current stepper driver carrier with SPI: AMIS-30543
This new board is a Pololu carrier for ON Semiconductor’s AMIS-30543 Micro-Stepping Motor Driver, which is a high-performance stepper motor driver with advanced features not found on our other stepper motor driver carriers.
AMIS-30543 stepper motor driver carrier, bottom view with dimensions. |
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The Pololu AMIS-30543 Stepper Motor Driver Carrier breaks out all of the important pins of the driver onto breadboard-compatible 0.1"-spaced pins, with optional terminal blocks for the power and motor connections and mounting holes for a more robust setup. Our board supplies reverse protection and all the necessary circuit components for interfacing to a microcontroller.
The AMIS-30543 is rated up to 30 V and 3 A, but (as with other stepper drivers) the current rating is a theoretical maximum assuming excellent cooling. Using our board at room temperature without a heatsink, the chip can practically supply about 1.8 A per coil, more than any of our other stepper motor driver carriers.
The SPI interface of the AMIS-30543 provides many exciting features: it lets you configure microstepping (down to 1/128-step), set the current limit, select voltage slopes, change direction, disable the outputs or put the driver to sleep, monitor the micro-step position and errors, and more. Please note, however, that you cannot step the motor over SPI.
Many of our customers have asked for software current limit control, since it allows better power management. For example, consider that stepper motors counter-intuitively use their maximum current when stopped, even if there is no holding torque required. This wastes a lot of power and generates undesirable heat in the drivers and motors. In a typical application like a 3D printer, where you don’t need much holding torque, you would want to reduce the current limit to a low value during pauses. You might use a higher limit (above the continuous limit) when accelerating and an intermediate value for constant-speed motion. The SPI current limit control on the AMIS-30543 lets you do all of this in your code.
Another advanced feature is the SLA (speed and load angle) output that indicates the level of the back-EMF voltage of the motor. This is an analog signal that can be used for stall detection or closed-loop control of the torque and speed:
AMIS-30543 stepper motor driver SLA output (green) and motor output (blue). |
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It is easy to get started using our Arduino library on GitHub, which provides basic functions for configuring and operating the driver as well as access to many of the advanced features. Please visit the product page for a detailed description, wiring diagrams, the AMIS-30543 datasheet, and more.
More new distributors
See the full list of over 200 distributors to find one in your area.
New distributors in Turkey
We have not been keeping up with announcing our new distributors on the blog, and I will be trying to catch up over the next week or two. To start with, I am excited to welcome two new Pololu distributors located in Istanbul, Turkey!
Robot Kutusu (officially Robkut Robot Teknolojileri Elektronik ve Otomasyon) is a distributor of Arduino, Raspbery Pi, and many other electronics and robotics products. They are now carrying a number of Pololu products, including wheels, motors, stepper motors, and the Zumo and 3pi robots.
F1 Depo and Robot Kutusu join our five other Turkish distributors. See the full list of over 200 distributors to find one in your area.
New product: Zumo 32U4
I am excited to announce the release of our new Zumo 32U4 Robot Kit, a complete Arduino-compatible robot kit based on the ATmega32U4. We have, in some sense, been working on this robot for about seven years.
One of our major long-term goals at Pololu is to be making complete robots, and many of the parts we make are stepping stones toward that goal. The first real step toward the Zumo started back in 2008, shortly after we started carrying our micro metal gearmotors, when we released the compatible wheels shown at right. The intent was that they could be used with either tires or tracks and optionally with encoders, and that eventually they would be a part of our own robot.
A few years later we had assembled enough parts to release the Zumo chassis. We planned to use this as the base for a complete robot, but by releasing it first as a component, we got to see the community do a lot of interesting things with it. (Check out this Raspberry Pi Zumo, for example.)
It was not until 2012 that we were able to announce a complete robot, the Zumo Robot Kit for Arduino, which combined all of these parts with a new board containing a boost regulator, motor drivers, and inertial sensors. The board works like an upside-down shield: you plug an Arduino onto the top of the robot. We released a compatible reflectance sensor array soon after that, making it possible to use the Zumo for everything from mini-sumo to maze-solving.
So we sort of had a new complete robot, but it was not quite complete enough for us, since it still required a separate Arduino, which we did not manufacture. Also, the upside-down shield configuration blocked a lot of space for expansion and prototyping, we lacked a good solution for obstacle/opponent sensing (that’s important for mini-sumo!), and we had received lots of requests for encoders, which are hard to squeeze into the available space. A lot of our effort in 2013 and 2014 went toward components that we thought could be used on a more complete Zumo, such as smaller quadrature encoders and 38 kHz IR proximity sensors. And developing our A-Star 32U4 line of Arduino-compatible controllers based on the ATmega32U4 helped integrate the Arduino functionality directly into the robot.
So finally we had all the pieces available to make a new, much more capable Zumo that would be completely Pololu, the Zumo 32U4 robot:
The Zumo 32U4 incorporates many features of the A-Star 32U4 Prime LV, including an ATmega32U4 microcontroller with an Arduino-compatible USB bootloader and a step-up/step-down voltage regulator system. There is a handy 8×2 character LCD on top and a buzzer for simple beeps and music. Like the Zumo Robot for Arduino, our kit includes dual motor drivers, a complete 9-axis IMU, and line sensors, but the new integrated quadrature encoders and proximity sensors make this a far more capable platform.
We are initially offering the Zumo 32U4 robot only as a kit. Soldering is required, and it is intended for more advanced or ambitious electronics builders. There are a number of build options – two different kinds of IR LEDs are included and you choose your motor gear ratio – and the construction gives you opportunities to show off your craftsmanship. Some Pololu engineers, for example, have been 3D-printing custom LED holders that mount onto the blade of their Zumos. The Zumo is also expandable; almost all of the I/O lines of the ATmega32U4 and the power and ground nodes are available on arrays of through-holes at the sides and front of the board, and with its low-profile design (you can remove the LCD) there is plenty of room to build on top.
While we hope we have left enough room for physical customizations, the programming, with all the sensing options, is where you can really give your robot personality and make it your own. Modulate the IR emitters for more precise opponent detection, use the accelerometer to detect a bump or a flip (sans LCD, the Zumo can drive upside down), measure distances with the encoders, measure turns with the gyros, … we are looking forward to see what you will come up with!
As we gain experience with the Zumo 32U4 robot and collect feedback from the community, we plan to release more supporting materials and offer assembled options. Our goal is to get it to the point where we can recommend the Zumo to anyone looking for a high-performance programmable robot – hobbyists, students, educators, and others – so stay tuned! Please check out the product page for more details about the robot, and take a look at our example code on GitHub.
Valentine's 3-Day Sale
Engage your brain as well as your heart this Valentine’s Day by picking up some of our perfectly matched pairs of products at a sweet discount. From Friday through Sunday we will have more than 100 items on sale at up to 20% off. You can find all the deals on our Valentine’s 3-Day Sale page.